Fluorescence and sensitization performance of phenylene-vinylene-substituted polythiophene

A new kind of polythiophene derivative, Poly(3-{2-[4-(2-ethylhexyloxy)-phenyl]-vinyl}-2,2′-bithiophene) (PTh), was applied in dye-sensitized solar cell to extend the light response of nanocrystalline TiO2 electrode. UV-vis absorption and fluorescence spectra were employed to investigate the interaction of PTh with nanocrystalline TiO2. The absorption coefficient of the PTh was high in visible part of spec- trum, and the fluorescence emission of the PTh can be efficiently quenched by TiO2 nanoparticles ow- i...     

I-V andC-V properties of TiO2 thin film by pulsed-laser reactive deposition

TiO-2 thin films have bee deposited on p-Si(111) substrates by pulsed-laser ablation of metallic Ti target in the O-3 ambient. The current-voltage and capacitance-voltage of the Al/TiO-2/Si capacitors are measured. The results show that the dielectric constant of thin film after being annealed at 700℃ is found to be 46, and the border trap density and the interface state density at the TiO-2/p-Si interface are 1.8×10 12 cm -2 and 2×10 12 eV -1·cm -2, respectively. The conduction mechanisms of as-deposited films are also discussed.     

Magnetoresistance of the thin film ferromagnetic nanoconstrictions

The magnetoresistance and I-V characteristics at different temperatures of the thin film ferromagnetic nanoconstrictions of variable width (from 20 to 250 nm) and 10 nm thicknesses, fabricated by electron beam lithography and vacuum thin film deposition are compared. The magnetoresistance and resistance of the thin film ferromagnetic nanoconstrictions are not related to the width of the nanoconstrictions. Instead the resistance of the local nano-region in the middle of the thin film ferromagnetic nanoconstriction has only a minor role compared to that of the two microscale thin film ferromagnetic electrodes, which contribute the majority of the measured resistance. The magnetoresistances of the thin film ferromagnetic nanoconstrictions and a 0.2 cm × 0.8 cm thin ferromagnetic film deposited under the same conditions were also compared; the thin film ferromagnetic nanoconstrictions have higher magnetoresistances than the thin ferromagnetic film, which implies that the measured magnetoresistance of the thin film ferromagnetic nanoconstrictions comes mainly from the local nano-region in their centers. In conclusion, the measured magnetoresistance of the whole sample is similar to the anisotropic magnetoresistance, because the resistance of the two microscale thin film ferromagnetic electrodes is much higher than that of the local nano-region in the middle of the samples. Comparing the experimental results for the thin film ferromagnetic nanoconstrictions and the thin ferromagnetic film reveals that the magnetoresistance of the local nano-region in the middle of the sample is much higher than that of the two microscale thin film ferromagnetic electrodes attached to it.     

Well-defined bis（phenolate） lanthanide methoxides as efficient initiators for the polymerization of cyclic carbonate and lactide

Lanthanide methoxides supported by carbon-bridged bis(phenolate) ligands 2,2′-methylene-bis(6-tert- butyl-4-methylphenoxo) (MBMP2-) [(MBMP)Ln( μ-OMe)(THF)2]2 (Ln = Nd (1), Yb (2)) were synthesized in high yields by the protolysis reaction using (C5H5)3Ln(THF) as starting materials, and complex 1 was structurally characterized. The coordination geometry around the center metal can be best described as a distorted octahedron. Complexes 1 and 2 were shown to be efficient initiators for the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) and L-lactide. The mechanism of DTC polymerization was explored by the end group analysis of the oligomer.     

Light scattering characteristic of TiO2 nanocrystalline porous films

TiO2 nanocrystalline porous films consisting of binary particles mixture (mean diameters of 12 and 100 nm) are capable of increasing the light absorption due to the possession of large specific surface area and light scattering property. The simultaneous reduction of the film thickness leads to a decrease of the recombination loss during electron transport and an increase of the photocurrent efficiency.     

A novel method for preparing platinized counter electrode of nanocrystalline dye-sensitized solar cells

The platinized FTO glass counter electrode was prepared by employing techniques of colloid preparation, Langmuir-Blodgett film and serf-assembly. The present electrode had very low platinum loading, high catalytic activity for iodine/triiodide reduction reaction. Compared with the conventional counter electrodes used in nanocrystalline dye-sensitized solar cells, the present electrode had provided a much higher catalytic performance which was attributed to the structure of platinum nanoclusters distributed homogeneously on the electrode.     

Synthesis of TiO2 nanotubes film and its light scattering property

TiO2 nanotubes with diameters of 10 nm and lengths up to 600 nm were fabricated by directly using commercial TiO2 powders P25 as the precursors via sonication-hydrothermal combination approach. TiO2 nanotubes were characterized by means of X-ray powder diffractometer （XRD）, scanning electron microscope （SEM）, selected area electron diffraction pattern （SAED） and transmission elec- tron microscope （TEM）. The light scattering property of film electrodes modified with TiO2 nanotubes was studied and revealed that TiO2 nanotubes can be used as the light scattering centers to increase the light absorption in dye-sensitized solar cells. The TiO2 nanotubes film electrodes mixed with 10% small nanoparticles TiO2 had both strong light scattering property and fine mechanical characteristics, and this kind of electrodes can be used as electrodes in improving the conversion efficiencies of dye-sensitized solar cells.     

Inhibition of bromophenols against PTP1B and anti-hyperglycemic effect of Rhodomela confervoides extract in diabetic rats

Protein tyrosine phosphatase 1B (PTP1B) plays an important role as a negative regulator in insulin signaling pathways. PTP1B is an effective target for the treatment of type 2 diabetes mellitus. Four bromophenol derivatives from red algae Rhodomela confervoides, 2,2′,3,3′-tetrabromo-4,4′,5,5′-tetra- hydroxydiphenyl methane (1), 3-bormo-4,5-bis(2,3-dibromo-4,5-dihydroxybenzyl) pyrocatechol (2), bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (3) and 2,2′,3-tribromo-3′,4,4′,5-tetrahydroxy-6′-ethyloxy- methyldiphenylmethane (4) showed significant inhibitory activity against PTP1B (IC50 were 2.4, 1.7, 1.5 and 0.84 μmol/L, respectively) as potential therapeutical agents for the treatment of type 2 diabetes mellitus. The anti-hyperglycemic effects of the ethanol extracts from R. confervoides on streptozoto- cin-induced diabetes (STZ-diabetes) in male Wistar rats fed with high fat diet were investigated. The STZ-diabetic rats treated with medium-dose and high-dose alga extracts showed remarkable reductions in fasting blood glucose (FBG) as compared with the STZ-diabetic control. The results indicate that the in vivo anti-hyperglycemic activity of the R. confervoides extracts can be partially attributed to the in- hibitory actions against PTP1B of the bromophenol derivatives and that may be of clinical importance in improving the management of type 2 diabetes mellitus.     

Electroluminescent property of tetrakis(phenyl)porphyrin carbonyl ruthenium(Ⅱ)

Luminescent tetrakis(phenyl)porphyrin carbonyl ruthenium (Ⅱ) (RuTPPCO) complex was employed as a doped emitting material to fabricate red organic electroluminescent (EL) devices. The EL device structure was [ITO/copper phthalocyanine (Cu-Pc) (15.0 nm)/N,N′-di(α-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4, 4′-diamine (NPB)(60.0 nm)/tris(8-hydroxyquinolinato)aluminum (Alq3):RuTPPCO (50.0 nm)/LiF (1.0 nm)/Al (200.0 nm)]. The codeposited films of Alq3:RuTPPCO were utilized as the emitting layer to construct EL devices. Experimental results showed that energy transfer from Alq3 to RuTPPCO occurred in the codeposited films. The EL property of the codeposited Alq3:RuTPPCO films with different RuTPPCO concentrations was described. For the EL device with the RuTPPCO concentration of 15% by weight, deep red electroluminescence at 656 nm with the maximum EL efficiency of 0.32 cd/A was achieved.     

Cellular prion protein imaging analysis with aptamer-labeled Ru（bpy）32＋-doped silica nanoparticles

A new type of highly selective aptamer-labeled fluorescent silica nanoparticles [Apt-tris（2,2＇-bipyri- dyl）ruthenium（II）@SiO2 NPs] were prepared through the reverse microemulsion method by using prolonged fluorescence lifetime ruthenium complexes of tris（2,2＇-bipyri- dyl）ruthenium（II） （Ru（bpy）2＋） as the source of the fluorescence for cellular prion protein imaging. Investigations showed that the newly prepared Ru（bpy）32＋@Si02 NPs possessed superior advantages of strong fluorescence, low toxicity, and easy surface modification for bioconjugation. Cell imaging experiments indicated that Apt- Ru（bpy）32＋@SiO2 NPs had great tendency to human bone marrow neuroblastoma cells （SK-N-SH cells）, since they can express large amount of prion protein on the surface of the cell, while in HeLa cells this phenomenon disappeared for the reason that HeLa cells cannot express prion proteins.     

Influence of substrate metals on the crystal growth of AlN films

AlN films were deposited by reactive radio frequency (RF) sputtering on various bottom electrodes, such as Al, Ti, Mo, Au/Ti, and Pt/Ti. The effects of substrate metals on the orientation of AlN thin films were investigated. The results of X-ray diffraction, atomic force microscopy, and field emission scanning electron microscopy show that the orientation of AlN films depends on the kinds of substrate metals evidently. The differences of AlN films deposited on various metal electrodes are attributed to the differences in lattice mismatch and thermal expansion coefficient between the AlN material and substrate metals. The AlN film deposited on the Pt/Ti electrode reveals highly the c-axis orientation with well-textured columnar structure. The positive role of the Pt/Ti electrode in achieving the high-quality AlN films and high-performance film bulk acoustic resonator (FBAR) may be attributed to the smaller lattice mismatch as well as the similarity of thermal expansion coefficient between the deposited AlN material and the Pt/Ti electrode substrate.     

Synthesis and characterization of carbon-bridged bis(phenolate) lanthanum alkoxides and their catalytic behavior for the polymerization of L-lactide

Four lanthanum alkoxides stabilized by a carbon-bridged bis(phenolate) ligand were synthesized and their catalytic behavior for the ring-opening polymerization of L-lactide was explored. Reactions of [(MBMP)LaCp(THF) 2 ] (MBMP 2 = 2,2′-methylene-bis(6-tert-butyl-4-methyl phenoxo)) with HOCH 2 Ph, HOCH 2 CF 3 , HOCH(CH 3 ) 2 , and HOCH 2 CH 2 N(CH 3 ) 2 , respectively, in a 1:1 molar ratio in THF gave the dimeric lanthanum alkoxo complexes [(MBMP)Ln(μ-OR)(THF) 2 ] 2 (OR = OCH 2 Ph(1), OCH 2 CF 3 (2), OCH(CH 3 ) 2 (3), OCH 2 CH 2 N(CH 3 ) 2 (4)]. These complexes were well characterized, and the definitive molecular structure of complex 1 was determined. It was found that complexes 1 to 4 are efficient initiators for the ring-opening polymerization of L-lactide. The structure of the alkoxo groups has a significant effect on the catalytic behavior, and complex 2 can initiate L-lactide polymerization in a controlled manner.     

Wearable supercapacitor self-charged by P(VDF-TrFE) piezoelectric separator

Flexible piezoelectric self-charging supercapacitors(PSCS) are capable of converting random mechanical energy directly into electric energy and providing sustainable power source for various wearable electronic devices.In this work,using PDMS-rGO/C hybrid membrane as the positive and negative electrodes,P(VDF-TrFE) film as the piezoseparator,a flexible and ultralight PSCS was developed to harvest the mechanical energy of human finger curvature and simultaneously store as chemical energy in supercapacitors.The PSCS can be efficiently charged from finger deformation in the presence of polarized P(VDF-TrFE) separator film.When the finger was bended to90°,the fabricated PSCS achieved a potential window of 0.45 V with the discharging time of about 18.0 s,and a stable charging current of 6.4 μA,providing a promising power solution to the next-generation self-powered wearable electronics system.     

Structural and mechanical properties of amorphous carbon films deposited by the dual plasma technique

Direct current metal filtered cathodic vacuum arc (FCVA) and acetylene gas (C₂H₂) were wielded to synthesize Ti-containing amorphous carbon films on Si (100). The influence of substrate bias voltage and acetylene gas on the microstructure and mechanical properties of the films were investigated. The results show that the phase of TiC in the (111) preferential crystallographic orientation exists in the film,and the main existing pattern of carbon is sp2. With increasing the acetylene flow rate,the contents of Ti and TiC phase of the film gradually reduce; however,the thickness of the film increases. When the substrate bias voltage reaches -600 V,the internal stress of the film reaches 1.6 GPa. The micro-hardness and elastic modulus of the film can reach 33.9 and 237.6 GPa,respectively,and the friction coefficient of the film is 0.25.     

Effects of binders on the performance of electric double-layer capacitors of carbon nanotube electrodes

Polarizable electrodes of electric double layer capacitor (EDLCs) were made from carbon nanotubes. Effects of different binders, which are phenolic resin (PF) and polytetrafluoroethylene (PTFE), on the properties of polarizable electrodes are studied. Results indicate that the microstructure, pore size distribution and specific capacitance of the electrodes with PTFE binder are superior to those electrodes with PF binder after carbonization. The suitable binder (PTFE) for carbon nanotubes electrodes is proposed.     

Study on Microcrystaline Structure and Luminescence of ZnS Thin Film Devices

Zinc sulfide is a type of Ⅱ-Ⅵ semiconductor comp ou nd with wide band gap. Having high brightness and low consumption, the thin film devices of zinc sulfide have broad prospects for application. These have made t hem attractive for popularity. In order to improve the luminescence characterist ics of the devices, recently, the investigation on electroluminescence(EL) thin film devices have been turning from macro properties to microstructure area. In this paper, we made the thin film devices of ZnS:Cu,Cl,...     

Fabrication of organically modified oxygen sensing film based on fluorescent quenching

An organically modified silicate (ORMOSIL) as a matrix for oxygen-sensitive sensor, in which di-methyldimethoxysilane was selected as an organic modifier in the precursor, is described. The sensing film with tris-(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) as an indicator developed in this paper was characterized by efficient quenching by oxygen. Blue light-emitting diodes (λmax = 475 nm) were employed as light excitation source. The linear range of the dissolved oxygen was from 0.5 to 16 μg/mL. The measured RSD was 2%, the response time (t95) was 60 s, and the determination limit was 0.2 μg/mL. A portable and inexpensive luminescence-based sensor was established and applied to the determina-tion of dissolved oxygen in the surface water.     

Protection of phosphatidylcholine to photosystem Ⅱ membrane during heat treatment

Photosystem Ⅱ membrane was reconstituted with phosphatidylcholine (PC) with different kinds of fatty acyl chains and the protection of PC to photosystem Ⅱ (PS Ⅱ)membrane during heat treatment was investigated using oxygen electrode, variable fluorescence and circular dichroism (CD) spectroscopy. Heat treatment decreased the oxygen evolution rate and the F′v/Fm′ ratio of PS Ⅱ membrane and influenced CD spectra of PS Ⅱ membrane, but PC inhibited the effect of heat treatment on the oxygen evolution rate, the F′v/F′m ratio and CD spectra of PS Ⅱ membrane. The results indicate that PC can protect PS Ⅱ membrane against heat treatment and the alterations in the unsaturated fatty acid extent in PC can cause the changes of the protection ability.     

In Situ Characterization of Polymer Matrices for Bio-electrode Applications

1 Results Electropolymerized azines are considered an important group of mediators for NAD / NADH-based biocatalytic applications[1].Characterizing these electroactive polymers in situ on electrode surface is vital to understand their behavior and properties.We recently studied the polymer deposition on electrodes using imaging ellipsometry (IE) as an in situ technique[2].The observation of surface morphology development can be conducted in cyclic voltammetric cycles in a nanometer scale.We then combined with quartz crystal microbalance (QCM) to monitor layer-by-layer polymer growth in terms of morphology,mass,charge,and film thickness progression,which allows a more mechanistic understanding of the steps involved in the electrochemical polymerization process.This electrochemical microgravimetric imaging ellipsometry (EmIE) technique enables us to distinguish mass change due to adsorption against redox reactions during cyclic voltammetry,offering a direct observation of electrode process in a non-invasive,in-situ manner.Such a capability promises nano-scale observations of electrode surface with direct correlation of mass,charge,and film property changes,with broad implications for kinematic studies of redox systems at interfaces.     

Structural and optical analysis of Cr_2N thin films prepared by DC magnetron sputtering

Chromium nitride(Cr2N) thin films were prepared by a DC magnetron sputtering technique. The deposition temperature was raised from 50 to 300°C, and its influence on the film structure and refractive index was investigated. X-ray diffraction analysis shows that the crystalline structure of the films transforms from the(101) to(002) oriented hexagonal Cr2 N phase as the increase of substrate temperature above 50°C, and a highly textured film grows at 100°C. An empirical relation between the crystalline orientation and infrared active modes of the films is obtained, i.e., the Fourier transform infrared(FTIR) spectrum of the film prepared at 50°C exhibits only A1(TO) mode. The prominent peak in the FTIR spectra of the film prepared above 50°C is assigned to the E1(TO) mode and is correlated with the(002) or c-axis oriented hexagonal wurtzite phase of Cr2 N. In the surface analysis of atomic force microscopy, a transformation from the featureless surface to columnar-type morphology is observed with the increase of substrate temperature from 50 to 100°C, exhibiting c-axis oriented crystallite growth. A further increase in substrate temperature to 200°C causes the c-axis crystallites to merge, resulting in the formation of voids. The refractive index(n) of the deposited films is obtained using spectroscopic ellipsometry.